“Ida” is a Holocaust movie, albeit one that never shows the events and only explicitly mentions it a handful of times. Among the genre, it’s one of the most unique and the most mordant, which is not to say it doesn’t take the subject seriously. It concerns the way trauma survives, resting in the undercurrents of society, persisting no matter how much people try to ignore it — or, for that matter, confront it.

The characters in “Ida” do both. It’s 1960 Poland, and a young, pretty nun (Agata Trzebuchowska) orphaned by WWII finally has the chance to meet her only relative. Through Wanda (Agata Kulesza), a boozing former prosecutor and her aunt, she discovers a few key things: Her name’s not Mary but Ida, and her parents, murdered during the Nazi occupation, were Jewish. This odd couple hit the road to find their grave, during which Ida gets exposed to the things from which her cloistered existence has shielded her: sex, drinks, cigarettes and John Coltrane. Whether or not she'll come to like them is another story.

But not so fast: This isn’t some heartwarming film about self-discovery. In fact, the lessons they learn, though few, don’t usually stick or wind up steering the plot in unexpected directions. The main story is even resolved much earlier than expected, leading to a dodgy but ultimately daring final act. Throughout, the tone is perched somewhere between miserable Wanda and remote Ida, who have two very different ways of keeping humanity at arm's length. All the warmth is either elided or toned down so that the film feels deadpan, if not outright muted.

This a clipped and strident film, told in a highly stylized manner that mimics the European art films of the period. Co-writer/director Pawel Pawlikowski — back home after English-language films like “My Summer of Love” — shoots in not only black-and-white but in the old box-shaped academy ratio of the period. It looks like one of Milos Forman’s old Czech films, like “Loves of a Blonde,” though its tone is even more “modern,” more cranky, more distant. Pawlikowski likes to frame his shots with his characters placed in unusual positions — at the bottom, off to the side, buried in a long shot — anything to match the detachment its characters struggle to maintain, even as they deal with humanity at its worst.